Apparatus and method for reducing low frequency vibrations in power tools

ABSTRACT

A power tool having a low frequency reduction apparatus includes a first handle portion, a second handle portion, and a dual-density bladder disposed between the first and second handle portions. By disposing such bladder accordingly, the second handle portion is effectively isolated from the first handle portion, thus reducing the low frequency vibrations transmitted to the second handle portion. Preferably, a gap is formed between the first and second handle portions. In another embodiment of the invention, a dual-density bladder between a handle portion and a main housing portion of the power tool.

FIELD OF THE INVENTION

This invention relates generally to power tools and, more particularly,to apparatus and methods for reducing low frequency vibrations in powertools.

BACKGROUND OF THE INVENTION

Many individuals are exposed to hand-induced vibrations by usinghand-held vibrating or repeated impact-type power tools that include,but are not limited to, chipping hammers, jackhammers, riveters, jacklegdrills, rotary grinders and sanders, orbital sanders, chain saws, lawnmowers, hammer drills, and string trimmers. These vibration levels canbe reduced by redesigning the tool or object or by placing a vibrationisolation device between the hand and the tool or object that is beingclasped by the hand. For example, prior art solutions include providinga rubber layer on the tool handle. However, such solutions are notcompletely satisfactory as they do not reduce low frequency vibrations,i.e., vibrations having frequencies lower than 120 Hertz.

Accordingly, it is the object of the present invention to provide amethod and apparatus for reducing low frequency vibrations in powertools.

SUMMARY OF THE INVENTION

The object of this invention is met by providing a dual-density bladderbetween a first and a second handle portion. By disposing such bladderaccordingly, the second handle portion is effectively isolated from thefirst handle portion, thus reducing the low frequency vibrationstransmitted to the second handle portion.

Similarly, the object of this invention is met by providing adual-density bladder between a handle portion and a main housingportion.

Additional features and benefits of the present invention are described,and will be apparent from, the accompanying drawings and the detaileddescription below.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate preferred embodiments of theinvention according to the practical application of the principlesthereof, and in which:

FIG. 1 is a partial side view of a power tool handle having a firstembodiment of the present invention;

FIG. 2 is a partial cross-sectional side view of the first embodimentalong the circle shown in broken lines of FIG. 1; and

FIG. 3 is a partial cross-sectional side view of a power tool handlehaving a second embodiment of the present invention.

DETAILED DESCRIPTION

The invention is now described with reference to the accompanyingfigures, wherein like numerals designate like parts. Referring to FIG.1, a preferred handle 10 of a power tool is provided with a rear portion11 attached to the main portion 15 via a plurality of screws 12.

Referring to FIG. 2, a dual-density bladder 13 is interposed between therear portion 11 and the main portion 15. Preferably, the bladder 13 isdisposed wherever a screw 12 couples the rear portion 11 with the mainportion 15.

Further, the bladder 13 may be constructed from a relatively firm,air-tight material, such as solid rubber, plastic, elastomeric material,etc. In addition, the bladder 13 includes a chamber 20, which is in turnfilled with a gas, fluid, or solid having a different density than thebladder material. For example, the bladder 13 may contain air,pressurized air, rheopexic fluid, foam, etc.

A person skilled in the art will recognize that the bladder 13 caninclude a plurality of cavities or cells, instead of a single chamber.Similarly, a person skilled in the art will recognize that differentmaterials can be used for constructing and/or filling the bladder 13.

Referring to FIG. 2, a gap 14 is created by interposing the bladder 13between the rear portion 11 and the main portion 15. Accordingly, thedual-density bladder 13 in effect isolates the rear portion 11, reducingthe low frequency vibrations transmitted to the rear portion 11.

Similarly, referring to FIG. 3, a larger bladder 13a can be disposedwithin the hollow portion of the handle, creating a gap 14 between therear portion 11 and the main portion 15.

Persons skilled in the art may recognize other comfort features that canbe added to the embodiments described above, such as providing thehandle with an outer rubber layer or gas- or fluid-filled layer.Similarly, persons skilled in the art may recognize other alternativesto the means disclosed herein, such as placing the bladders so that theentire handle is isolated from the power tool. However, all theseadditions and/or alterations are considered to be equivalents of thepresent invention.

I claim:
 1. A power tool comprising:a first handle portion, a secondhandle portion, and a dual-density bladder disposed between the firstand second handle portions.
 2. The power tool of claim 1, wherein a gapis formed between the first and second handle portions.
 3. A power toolcomprising:a handle portion, a main housing portion, and a dual-densitybladder disposed between the handle portion and the main housingportion.
 4. The power tool of claim 3, wherein a gap is formed betweenthe first and second handle portions.